Apple's in the eye of flaw finders

At the recent ShmooCon hacking conference, one security researcher found out the hard way that such venues can be hostile, when an unknown hacker took control of the researcher's computer, disabling the firewall and starting up a file server.

While such compromises have become common in the Windows world, this time the computer was an Apple PowerBook running the latest version of Mac OS X. The victim, a security researcher who asked to remain anonymous, had locked down the system prior to the conference and believes that a previously unknown exploit caused the compromise. However, in the following weeks, forensics performed on the system did not reveal any clues as to how the PowerBook had been compromised.

"The machine was as hardened as best practices could suggest for anyone," the researcher said. The person who breached the PowerBook used information gathered from the computer to contact a friend of the researcher and bragged about the compromise. "This was not a subtle hack," the researcher stressed.

The compromise underscores a number of trends that has already caused a shift in focus among flaw finders and could result in more attacks on Mac OS X. Security researchers themselves have moved over to Apple computers in the past few years and have learned the ins and outs of the operating system. The company's move to Intel-based hardware for its next-generation of Macs also gives flaw finders familiar territory in which to look for bugs. Finally, as Apple continues to garner more market share, the lure of a larger set of targets will make attacks more likely, say security researchers.

"This is almost certainly the year of the OS X exploit," said Jay Beale, a senior security consultant for Intelguardians and an expert in hardening Linux and Mac OS X systems. "The OS X platform may be based on a Unix platform, but Apple seems to be making mistakes that Unix made, and corrected, long ago."

Apple also has been widely criticised for not talking about the details of its vulnerability-response process or how it manages security incidents. While Microsoft has the lion's share of security problems - and the Mac OS X hardly any - the Redmond, Wash, based software giant has received high marks from security researchers for its responsiveness, while Apple has often been the focus of complaints.

"On a good day, Apple doesn't even make it to Microsoft's level of security awareness," Beale said.

The company has generally refused to discuss the security of its Mac OS X operating system with the media and declined to comment for this article. The security researcher whose PowerBook was compromised has discussed the issue with Apple but without any conclusions being reached.

Apple has made good decisions regarding the Mac OS X architecture and has had far fewer security problems as a result, said Adam Shostack, chief technology officer for security firm Reflective.

"There are some things that make the Mac more secure," Shostack said. "There is a user model that does not rely on a user running programs in administrator mode. There is no ActiveX in Safari and there is no ActiveX equivalent. That makes it harder to go to a web page and have your Mac compromised."

Yet, the platform is garnering more attention from the experts who search for vulnerabilities. Driven by the cool look of the Mac OS X and the ability to run most Unix and Linux security tools on the system, Apple's operating system has become popular among security researchers.

That popularity could be the reason that the number of vulnerabilities logged in Apple's Mac OS X surpassed the number of vulnerabilities found in Microsoft's Windows XP in 2004 and 2005, according to data from the National Vulnerability Database (NVD). Apple had to contend with 88 vulnerabilities (29 high severity ones) in the Mac OS X in 2005, up from 54 in the prior year, while Microsoft patched 61 vulnerabilities (38 deemed of high severity) in Windows XP in 2005, up from 44 the prior year, according to the NVD. The data does show that fewer of the flaws in Mac OS X were considered severe.

Such numbers always have to be taken with a grain of salt. Differing ways of reporting flaws, different editorial policies on the part of the vulnerability database staff, and differences between what software components are considered part of the operating system all combine to make vulnerability statistics less than authoritative.

However, some security researchers speculate that the number of flaws found in the future will increase. Apple's change to the Intel platform will put many security researchers in their comfort zone in dealing with the architecture. While the change will not mean much for application-level vulnerabilities, flaws in the memory architecture or in processor-specific functions could be found more easily, Reflective's Shostack said.

"OS X running on x86 means that the skills that people have developed and a lot of the tools people have created for finding problems, analysing problems, and writing the code to take advantage of them, will work," he said. "They no longer need to learn a different assembler or a different memory architecture."

Finally, the old adage about market share still holds, said Dan Kaminsky, an independent consultant for Doxpara Research. As Macs become more popular, attackers will tend to target the platform more often, he said.

"There just aren't that many Mac users right now," Kaminsky said. "As it gets put on more and more desktops, it becomes a pretty high-profile target in terms of what is your return on investment for committing an attack against the group."

Ironically, Apple's lack of experience with major attacks might also cause problems for the company and its users, Kaminsky said.

"The reality is that security work does comes from a trial by fire," he said. "And Apple really has not had that experience. It had not had the experience from some 20 years that Unix had and that Linux has absorbed. It has not had the experience that Microsoft had with its summer of worms."